The present invention relates to a heat generating body and, more particularly, to a heat generating body comprising a heat generating composition which can generate heat merely by a contact with oxygen in the air and a bag containing the heat generating composition.
Hitherto, various types of heat generating composition have been known which presents heat through a chemical reaction caused merely by a contact with air. Examples of such heat generating composition are: (1) a mixture of powders of metal such as iron, aluminum or the like and an oxidation assistant such as active carbon, electrolyte, water or the like; and (2) a mixture of a metal sulfide or polysulfide and carbonaceous material.
Such a heat generating material is packed in a container such as a bag made of an air-permeable material having an air-permeability sufficient for producing heat or a material which is inherently impermeable to air but perforated to permit air to pass therethrough. Such heat generating bodies are put into practical use as, for example, body warmers. The heat generating body is wrapped by and preserved in a material having low oxygen-permeability until it is used.
This type of heat generating body in one hand offers various advantages such as easiness and safety in use, but on the other hand suffers the following disadvantages. Namely, when this heat generating body is used as a human body warmer or as a heat source for heating mechanical equipment, parts or the like, the heat generating composition in the bag is undesirably distributed to the lower part of the bag by gravity to give quite and unnatural feel of use and to change the heat generating characteristics and reduce the amount of heat thus generated, not only when the heat generating body is subjected to a vibration or vigorous action but even when it is held stationarily.